This recipe is based on Alton Brown’s Sugar Cookie – with a couple changes to make gluten free.
Here is a link to his video on how to make sugar cookies:
Sift together flour, xanthan gum, baking powder, and salt. Set aside.
Place butter and sugar in large bowl of electric stand mixer and beat until light in color.
Add egg and milk and beat to combine. Put mixer on low speed, gradually add flour, and beat until mixture pulls away from the side of the bowl.
Divide the dough in half, wrap in waxed paper, and refrigerate for 2 hours.
Sprinkle surface where you will roll out dough with powdered sugar. Remove 1 wrapped pack of dough from refrigerator at a time, sprinkle rolling pin with powdered sugar, and roll out dough to 1/4-inch thick. Move the dough around and check underneath frequently to make sure it is not sticking.
Cut into desired shape, place at least 1-inch apart on parchment and bake for 7 to 9 minutes or until cookies are just beginning to turn brown around the edges, rotating cookie sheet halfway through baking time.
Let sit on baking sheet for 2 minutes after removal from oven and then move to complete cooling on wire rack. Serve as is or frost as desired.